- Removing (some) dead code and obsolete comments
- Switching to HashTrees as index of working memory.
- Using Comparator for ordering Terms; this allows null as Term in working memory.
- Rewriting changed to never create 0-ary rule heads; it creates 1-ary using a constant.
- Fixing a bug in the rewriting where variables were wrongly named.
- Fixing a bug in the rewriting where wrong rules were created.
- Fixing a bug in the JoinNode where a self-join did not produce all results.